Keloid Development Research Articles

CEMIP induces TGF-β/Smad signaling to promote keloid development by binding to SPARC

BackgroundCell Migration Inducing Hyaluronidase 1 (CEMIP) is a protein that plays regulatory functions in a variety of cellular processes in many diseases. Nevertheless, its role and molecular mechanism in keloid hyperplasia are still elusive. MethodsExpressions of CEMIP and Secreted Protein acidic and Rich in Cysteine (SPARC) were detected by qRT-PCR and western blot. CCK-8 assay, along with immunofluorescence staining, was applied for the assessment of cell proliferation. The capabilities of cells to migrate and invade were evaluated utilizing wound healing and Transwell, while Extracellular Matrix (ECM) deposition was measured by immunofluorescence and western blot. The interaction of CEMIP and SPARC was predicted by the Coexpedia and PPA-red databases and verified by co-IP. Western blot was adopted for the estimation of TGF-β/Smad pathway-related proteins. ResultsThe data demonstrated that CEMIP expression was elevated in Keloid Fibroblasts (KF). CEMIP interference suppressed cell proliferative, migrative and invasive capabilities and ECM deposition in KF. Mechanistically, bioinformatics analysis revealed that CEMIP was co-expressed with SPARC and CEMIP protein could bind to SPARC. SPARC expression was reduced in CEMIP-silenced cells. SPARC overexpression counteracted the impacts of CEMIP silencing on cell proliferative, migrative and invasive capabilities and ECM deposition in KF. In addition, the expressions of TGF-β/Smad signaling-related proteins were decreased by CEMIP silencing via the inhibition of SPARC. ConclusionIn summary, this study revealed that CEMIP modulated KF proliferation, migration, invasion and ECM deposition by TGF-β/Smad signaling through binding to SPARC.

Single-cell RNA sequencing highlights the role of proinflammatory fibroblasts, vascular endothelial cells, and immune cells in the keloid immune microenvironment.

Keloids, characterized by an aberrant wound-healing process and a highly complex immune microenvironment, pose significant challenges for clinical management. Fibroblasts and vascular endothelial cells (VEC) were identified as the leading cells of keloid development. However, their roles in the keloid immune landscape have yet to be thoroughly elucidated. To explore the functional state of cells in the immune landscape of keloids, we conducted a single-cell RNA sequencing analysis on the tissue from three keloid lesions and two specimens of healthy skin. We simultaneously utilized available keloid data from the public database for external validation. Specific subsets, such as proinflammatory fibroblasts (piF) and VEC, were markedly elevated in lesional skincompared to normal skin. Subsequent differential gene expression and Gene Ontology analyses indicated that these subsets may be involved in shaping the microenvironment. In keloids, there is an increased expression of immune-associated genes (P < 0.05), including TNFRSF6B, HGF, and TGFB3, alongside a decreased expression of inflammatory chemokines in the piF. Moreover, the significant upregulation of immune suppressive genes (P < 0.05), including CD39, CD73, and HIF1A, suggested the potential involvement of VEC as a conditional immune subpopulation in the keloid microenvironment. Immune cell communication analysis revealed preferential enrichment of macrophages and Tregs, highlighting intensified macrophage-centered interactions within the keloid microenvironment. Our study highlighted the role of piF and VEC in the immune microenvironment of keloids for the first time, providing potential targets for therapeutic development.

The inhibitory effect of type V transforming growth factor-β receptor antagonist on the proliferation of keloid fibroblasts by suppressing insulin-like growth factor-binding protein 3-interleukin-6 signaling

Abstract Background: Hyperplasia of fibroblasts is critical in keloid pathogenesis. Insulin-like growth factor-binding protein 3 (IGFBP3) is an important factor in the regulation of cell growth and type V transforming growth factor-β receptor (TβR-V) is a specific receptor of IGFBP3. However, the role of IGFBP3 in keloid development has not been reported. Objectives: This study aimed to investigate the role of IGFBP3 in keloid pathogenesis and evaluate the effects of TβR-V antagonist on keloid fibroblasts (KFs) activities. Methods: IGFBP3 expression in keloids and its impact on KF proliferation were examined. The effects of TβR-V antagonist on KF cell proliferation, migration, and invasion were also investigated. Differentially expressed genes (DEGs) between TβR-V antagonist treated and nontreated KFs were identified through RNA-sequencing (RNA-seq), followed by Gene Ontology (GO), Kyoto Encyclopedia of Genes and Genomes (KEGG), and protein–protein interaction (PPI) network analyses. Results: IGFBP3 was overexpressed in keloids and could promote KF proliferation. TβR-V antagonist suppressed KFs proliferation, migration, and invasion. GO and KEGG analyses showed that the downregulated DEGs revealed by RNA-seq were significantly enriched in terms related to cell proliferation. Interleukin-6 (IL-6) was identified as the only gene interacting with IGFBP3 in the PPI network and was associated with nine hub genes. In vitro assay confirmed the suppression of IL-6 by TβR-V antagonist in KFs. Conclusion: Our study demonstrated that TβR-V antagonist could inhibit keloid growth likely through suppressing IGFBP3-IL-6 signaling activation. These findings suggest that targeting TβR-V could be a potential therapeutic strategy for keloid treatment.

Increased Susceptibility to Mechanical Stretch Drives the Persistence of Keloid Fibroblasts: An Investigation Using a Stretchable PDMS Platform.

Keloids are a common fibrotic disease of the skin, with the pathological hallmark of excessive extracellular matrix synthesis due to abnormal fibroblast activity. Since keloids clinically arise in areas of high mechanical tension, the mechanotransductory pathway may be attributed to its pathogenesis. We aimed to establish a preclinical platform to elucidate the underlying mechanism of keloid development and its clinical persistence. We fabricated a mechanically stretchable polydimethylsiloxane cell culture platform; with its mimicry of the in vivo cyclic stretch of skeletal muscles, cells showed higher proliferation compared with conventional modalities. In response to mechanical strain, TGF-β and type 1 collagen showed significant increases, suggesting possible TGF-β/Smad pathway activation via mechanical stimulation. Protein candidates selected by proteomic analysis were evaluated, indicating that key molecules involved in cell signaling and oxidative stress were significantly altered. Additionally, the cytoskeletal network of keloid fibroblasts showed increased expression of its components after periodic mechanical stimulation. Herein, we demonstrated and validated the existing body of knowledge regarding profibrotic mechanotransduction signaling pathways in keloid fibroblasts. Cyclic stretch, as a driving force, could help to decipher the tension-mediated biomechanical processes, leading to the development of optimized therapeutic targets.

Development of Postsurgical Pyoderma Gangrenosum with New Keloid after Keloid Resection.

Keloids are a dermal fibroproliferative disorder and can arise from trauma, acne, vaccination, and herpes zoster. Pyoderma gangrenosum (PG) is a painful ulcerative skin disorder that is associated with neutrophilic dysfunction. However, the pathophysiologies of keloids and PG are not fully understood. The authors encountered an unusual case of a 24-year-old woman who presented with an anterior chest keloid that bore an ulcer. The keloid was resected along with the ulcer, and histology revealed the ulcer to be a neutrophilic PG ulcer. A year after surgery, another ulcer developed in the scar. The ulcer met the PARACELSUS criteria of a postsurgical PG ulcer. After treatment with systemic prednisone and adalimumab for 250 days, the ulcer re-epithelialized. However, relapsed keloids were then observed at the PG site. Corticosteroid taping may be the safest therapy for patients with a history of PG. Conversely, if there is suspicion that a patient is prone to keloid development, diagnostic biopsies and surgical management of PG ulcers should be avoided or conducted with care.

The fibroblast heterogeneity across keloid, normal and tumor samples from single-cell resolution.

Keloids are defined as a benign dermal fibroproliferative disorder, with excessive fibroblast proliferation, and excessive overproduction of collagen. Although the heterogeneity during keloid development has been extensively studied, the heterogeneity across different skin states is still unclear. So, a global comparison across skin states is needed. In this study, we collected samples from 5 states of skin, including melanoma, cutaneous squamous cell carcinoma, keloid skin, scar skin, and healthy control samples. The heterogeneity of cell types and subtypes was analyzed and compared across 5 states, and we observed significant differences among them. Our results showed a cancer-like fibroblast, which is not in normal samples, may play an important role in antigen processing and presentation. We also noticed that the mesenchymal fibroblast increased in keloid samples, which highly expressed POSTN. And POSTN may participate in epithelial-mesenchymal transition and collagen overexpression to promote keloid growth. These findings help to understand the alteration among different skin states and provide potential genetic basis for keloid therapies.

Targeting the Epigenome Reduces Keloid Fibroblast Cell Proliferation, Migration, and Invasion

Keloids are pathological fibroproliferative scars resulting from abnormal collagen deposition within and beyond the margins of the initial cutaneous insult. Keloids negatively impact quality of life functionally and cosmetically, with current treatment modalities unsatisfactory. Recent studies indicate that epigenetic dysregulation is central to the development and progression of keloids. Here we evaluate the functional significance of epigenetic targeting strategies in vitro using patient-derived keloid fibroblasts treated with small molecule inhibitors of HDACs, LSD1, CoREST and p300, as potential therapies for keloids. We find that both the dual-acting CoREST inhibitor, corin, and the HDAC inhibitor, entinostat, reduce fibroblast proliferation more than the LSD1 inhibitor, GSK-LSD1; additionally, corin was the most effective inhibitor of migration and invasion across keloid fibroblasts. RNA-seq analysis of keloid fibroblasts treated with corin demonstrates coordinate upregulation of many genes including key mediators of cell adhesion such as claudins. Corin also downregulates gene sets involved in cell cycle progression, including reduced expression of cyclins A1 and B2 compared to DMSO. These results highlight a significant role for epigenetic regulation of pathologic mediators of keloidal scarring and suggest that inhibitors of the epigenetic CoREST repressor complex may prove beneficial in the prevention and/or treatment of keloidal scarring in patients.

A Prospective Study of Patients Presenting With Pre-sternal Keloids.

Keloid represents a pathological form of scarring. They are very common in the anterior chest area; nearly 50% of all keloids occur in this location. One of the reasons for this is that folliculitis and acne, known for triggering the development of keloids, are common on the anterior chest. The other reason is the tension load in this area due to the frequent movements of the upper limbs and the respiratory movements. These movements stretch the skin of the anterior chest horizontally. When this cyclical tension is imposed on the anterior chest wounds, there is an exacerbation and prolongation of the inflammation in the reticular dermis of the wound. These stresses induce the growth of keloids along the prevailing lines of skin tension. We performed a prospective study in which patients were recruited over a period of one year. Patients presenting with symptomatic pre-sternal keloids and requesting treatment but were unwilling to undergo surgical intervention were included in this study. Patients with a history of previous thoracic surgery were excluded. Baseline assessment and documentation of the lesion were performed. The study patients received three sessions of intralesional injections of a combination of triamcinolone acetonide and hyaluronidase at four weekly intervals. The final assessment was performed four weeks after the third session. The study included 47 lesions in 47 patients with ages of the patients ranging from 16 to 70 years. Pre-sternal keloids were found to be more common among males than females, with a male-to-female ratio of 2.35:1. Patients presented with pre-sternal keloids that had been present for varying periods ranging from three to 81 months. All of our 47 patients completed the three sessions of the treatment. Following the treatment, there was an improvement in the patient's symptoms, as evidenced by the reduction in the mean pruritis scores and pain scores. There was an overall reduction in the size of the lesion. The decrease in the height of the lesions was more evident than the reduction in the craniocaudal or transverse dimensions of the lesions. There were improvements in Vancouver Scar Scale(VSS) vascularity scores and pliability scores following the treatment. We conclude that pre-sternal keloids should be considered as a distinct clinico-pathological entity. There are differences with regard to pathogenesis, clinical presentation, and management when compared to keloids elsewhere. Treatment with intralesional injections of a combination of triamcinolone acetonide and hyaluronidase effectively relieves the symptoms and may be considered in patients not willing to undergo surgical intervention. Recurrences can occur and need further treatments.

In the face and neck, keloid scar distribution is related to skin thickness and stiffness changes associated with movement.

Keloid scars tend to occur in high-tension sites due to mechanical stimuli that are involved in their development. To date, a detailed analysis of keloid distribution focused specifically on facial and neck areas has not been reported, and limited literature exists as to the related mechanical factors. To rectify this deficiency of knowledge, we first quantified the facial and neck keloid distribution observed clinically in 113 patients. Subsequently, we performed a rigorous investigation into the mechanical factors and their associated changes at these anatomic sites in healthy volunteers without a history of pathologic scarring. The association between keloid-predilection sites and sebaceous gland-dense and acne-prone sites was also examined. To assess skin stretch, thickness and stiffness, VECTRA, ultrasound and indentometer were utilised. Baseline skin stiffness and thickness were measured, as well as the magnitude of change in these values associated with facial expression and postural changes. Within the face and neck, keloids were most common near the mandibular angle (41.3%) and lateral submental (20.0%) regions. These areas of increased keloid incidence were not associated with areas more dense in sebaceous glands, nor linked consistently with acne-susceptible regions. Binomial logistic regression revealed that changes in skin stiffness and thickness related to postural changes significantly predicted keloid distribution. Skin stiffness and thickness changes related to prolonged mechanical forces (postural changes) are most pronounced at sites of high keloid predilection. This finding further elucidates the means by which skin stretch and tension are related to keloid development. As a more detailed analysis of mechanical forces on facial and neck skin, this study evaluates the nuances of multiple skin-mechanical properties, and their changes in a three-dimensional framework. Such factors may be critical to better understanding keloid progression and development in the face and neck.

47 Cross-ancestry GWAS meta-analysis of keloids discovers novel susceptibility loci in diverse populations

OBJECTIVES/GOALS: We aimed to conduct an updated genome-wide meta-analysis of keloids in expanded populations, including those most afflicted by keloids. Our overall objective was to improve understanding of keloid development though the identification and further characterization of keloid-associated genes with genetically predicted gene expression (GPGE). METHODS/STUDY POPULATION: We used publicly available summary statistics from several large-scale DNA biobanks, including the UK Biobank, FinnGen, and Biobank Japan. We also leveraged data from the Million Veterans Program and performed genome-wide association studies of keloids in BioVU and eMERGE. For each of these datasets, cases were determined from ICD-9/ICD-10 codes and phecodes. With these data we conducted fixed effects meta-analysis, both across ancestries and stratified by broad ancestry groups. This approach allowed us to consider cumulative evidence for genetic risk factors for keloids and explore potential ancestry-specific components of risk. We used FUMA for functional annotation of results and LDSC to estimate ancestry-specific heritability. We performed GPGE analysis using S-PrediXcan with GTEx v8 tissues. RESULTS/ANTICIPATED RESULTS: We detected 30 (23 novel) genomic risk loci in the cross-ancestry analysis. Major risk loci were broadly consistent between ancestries, with variable effects. Keloid heritability estimates from LDSC were 6%, 21%, and 34% for European, East Asian, and African ancestry, respectively. The top hit (P = 1.7e-77) in the cross-ancestry analysis was at a replicated variant (rs10863683) located downstream of LINC01705. GPGE analysis identified an association between decreased risk of keloids and increased expression of LINC01705 in fibroblasts (P = 3.6e10-20), which are important in wound healing. The top hit in the African-ancestry analysis (P = 5.5e-31) was a novel variant (rs34647667) in a conserved region downstream of ITGA11. ITGA11 encodes a collagen receptor and was previously associated with uterine fibroids. DISCUSSION/SIGNIFICANCE: This work significantly increases the yield of discoveries from keloid genetic association studies, describing both common and ancestry-specific effects. Stark differences in heritability support a potential adaptive origin for keloid disparities. Further work will continue to examine keloids in the broader context of other fibrotic diseases.

The regulatory role of the apelin/APJ axis in scarring: Identification of upstream and downstream mechanisms

Scarring, a prevalent issue in clinical settings, is characterized by the excessive generation of extracellular matrix within the skin tissue. Among the numerous regulatory factors implicated in fibrosis across various organs, the apelin/APJ axis has emerged as a potential regulator of fibrosis. Given the shared attribute of heightened extracellular matrix production between organ fibrosis and scarring, we hypothesize that the apelin/APJ axis also plays a regulatory role in scar development. In this study, we examined the expression of apelin and APJ in scar tissue, normal skin, and fibroblasts derived from these tissues. We investigated the impact of the hypoxic microenvironment in scars on apelin/APJ expression to identify the transcription factors influencing apelin/APJ expression. Through overexpressing or knocking down apelin/APJ expression, we observed their effects on fibroblast secretion of extracellular matrix proteins. We further validated these effects in animal experiments while exploring the underlying mechanisms. Our findings demonstrated that the apelin/APJ axis is expressed in fibroblasts from keloid, hypertrophic scar, and normal skin. The regulation of apelin/APJ expression by the hypoxic environment in scars plays a significant role in hypertrophic scar and keloid development. This regulation promotes extracellular matrix secretion through upregulation of TGF-β1 expression via the PI3K/Akt/CREB1 pathway.

Macrophage phenotype is determinant for fibrosis development in keloid disease

Keloid refers to a fibroproliferative disorder characterized by an accumulation of extracellular matrix (ECM) components at the dermis level, overgrowth beyond initial wound, and formation of tumor-like nodule areas. Treating keloid is still an unmet clinical need and the lack of an efficient therapy is clearly related to limited knowledge about keloid etiology, despite the growing interest of the scientific community in this pathology. In past decades, keloids were often studied in vitro through the sole prism of fibroblasts considered as the major effector of ECM deposition. Nevertheless, development of keloids results from cross-interactions of keloid fibroblasts (KFs) and their surrounding microenvironment, including immune cells such as macrophages. Our study aimed to evaluate the effect of M1 and M2 monocyte-derived macrophages on KFs in vitro. We focused on the effects of the macrophage secretome on fibrosis-related criteria in KFs, including proliferation, migration, differentiation, and ECM synthesis. First, we demonstrated that M2-like macrophages enhanced the fibrogenic profile of KFs in culture. Then, we surprisingly founded that M1-like macrophages can have an anti-fibrogenic effect on KFs, even in a pro-fibrotic environment. These results demonstrate, for the first time, that M1 and M2 macrophage subsets differentially impact the fibrotic fate of KFs in vitro, and suggest that restoring the M1/M2 balance to favor M1 in keloids could be an efficient therapeutic lever to prevent or treat keloid fibrosis.

TFCP2L1 as a potential diagnostic gene biomarker of Keloid given its association with immune cells-a study based on machine learning and RNA sequence

Keloids represent a specific type of dermal tumor, where delayed treatment greatly heighten risks of recurrence. This study thus seeks to identify key genes for early keloid diagnosis and compare how immune cell infiltration between keloid lesion skin (KLS) and keloid adjacent non-lesional skin (KNL) differ. Utilizing two GEO datasets, which encompassed KLS (n=8) and KNL (n=6) samples, 564 differentially expressed genes (DEGs) were identified, with a primary emphasis on inflammation- and fibrosis-related pathways. The gene TFCP2L1 was pinpointed from the intersection of LASSO and SVM-RFE algorithms, exhibiting downregulation in KLS when juxtaposed with KNL. To aid prognosis and identification of potential immunotherapy targets, the CIBERSORT algorithm was employed to assess prelative proportions of immune cells. In the KNL samples, there was an observed increase in follicular helper T cells, activated NK cells, and activated dendritic cells. Conversely, M1 macrophages were elevated in KLS samples. TFCP2L1 exhibited a positive correlation with activated NK cells and activated dendritic cells, while it showed a negative correlation with M1macrophages. These findings highlight the intertwined roles of TFCP2L1 and immune cell infiltration, lending to TFCP2L1’s potential as a diagnostic biomarker for keloids and highlights how TFCP2L1 might influence keloid development through immune cell populations.

(058) Evaluation of Pathway Expression Following Down-Regulation of NELL1, a Potential Gene of Interest in Peyronie’s Disease

Abstract Introduction Peyronie’s Disease (PD) is a superficial fibrosing disorder characterized by inelastic fibrous plaques within the tunica albuginea. We previously performed high-resolution array comparative genomic hybridization analysis of genomic DNA from men with both PD and Dupuytren’s Disease (DD), yielding candidate genes, including NELL1, with potential involvement in these conditions. NELL1 is a secreted growth factor that enhances osteoblastic differentiation and chondrogenesis and may contribute to calcification and inflammation in fibrotic plaques via its interaction with bone morphogenetic protein (BMP) within the TGF-β signaling pathway. Here, we report on pathway analysis following up- and down-regulation of NELL1 using CRISPR modification in an in vitro setting. Objective This study aimed to investigate the influence of NELL1 modification on downstream gene regulation, focusing on pathways that were significantly regulated following NELL1 down-regulation. Methods For down-regulation of NELL1, gRNAs were delivered to HEK293 cells with a nuclease deficient (d) dCas9-KRAB system adapted from Streptococcus pyogenes. Gene regulation was assessed using qRT-PCR. Results For down-regulation of NELL1, PCR analysis confirmed a 95% reduction in expression. Non-target vectors did not change NELL1 expression levels. RNA sequencing results found over 5,000 differentially expressed genes between, with significant changes in multiple pathways, including the HIF-1α pathway, which promotes keloid development by activating the TGF-β/Smad pathways. Additionally, we identified pathways related to ECM-receptor interaction, inflammation, apoptosis, and cell cycle regulation that are mediated by TGF-β/Smad signaling, which plays a crucial role in fibrosis. Our analysis also demonstrated upregulation of the PI3K-Akt pathway, which is involved in regulating type I collagen expression in response to TGF-β1. These results highlight the significance of NELL1 in fibrotic regulation and suggest its potential involvement in the development of PD. Conclusions We have created guides for and successfully down-regulated the expression of NELL1, a gene of interest in Peyronie’s disease. We have also demonstrated, through RNA sequencing, that changes in NELL1 lead to large changes in gene and pathway expression. The identified modified pathways, including HIF-1α-mediated, TGF-β/Smad and PI3K-Akt, provide valuable insights into the potential molecular mechanisms underlying NELL1's role in regulation of fibrosis, and further investigation of these pathways may reveal potential therapeutic targets for fibrosis-related disorders. Disclosure Any of the authors act as a consultant, employee or shareholder of an industry for: Contraline, Techfields Inc, Alto Neurosciences, Curebase.

Association of Human Leukocyte Antigens (HLA) with Keloids and Hypertrophic Scar in Thais

Background: Keloids and hypertrophic scars are abnormal fibro-proliferative lesions. Associations between genes, the human leukocyte antigen (HLA) system in particular, and keloids have been studied in various ethnic groups but not in Thais. Objective: To investigate the association of HLA alleles with keloids and hypertrophic scars in Thais. Materials and Methods: The present study employed a retrospective case-control design. Scar assessment was performed on 139 kidney donors who underwent nephrectomy at Ramathibodi Hospital between January 2008 and December 2015. The wound scars after nephrectomy were evaluated and graded by a plastic surgeon using the modified Vancouver Scar Scale. Kidney donors who were unable to communicate well or who had autoimmune diseases or complications from surgery were excluded from the study. The diagnosis of a keloid scar, hypertrophic scar, and flat scar was made by clinical criteria. The donors were categorized into groups with three scar types, flat as the control group, hypertrophic, and keloid. The associations between the frequencies of HLA antigen with hypertrophic scar and keloids were measured with an odds ratio using logistic regression analysis. Results: Of the 139 living kidney donors, 15 (10.8%) had keloids, 46 (33.1%) had hypertrophic scars, and 78 (56.1%) had flat scars. Sixty-one HLA-A, -B, -DRB1, and -DQB1 alleles were evaluated in the present study. Compared with controls, the allele frequency of HLA-DRB1*15 was significantly higher in the keloid group at 43.33% versus 24.36% (odds ratio 2.37, 95% confidence interval 1.06 to 5.33, p=0.036). No significant association between HLA alleles and hypertrophic scars was found. Conclusion: The present study demonstrated the positive association of HLA-DRB1*15 with keloids in Thai individuals. The HLA-DRB1*15 could be a susceptibility factor for the development of keloids. Keywords: Human leukocyte antigen; Keloids; Thais, HLA-DRB1; Positive association

Metabolism, fibrosis, and apoptosis: The effect of lipids and their derivatives on keloid formation.

Keloids, pathological scars resulting from skin trauma, have traditionally posed significant clinical management challenges due to their persistence and high recurrence rates. Our research elucidates the pivotal roles of lipids and their derivatives in keloid development, driven by underlying mechanisms of abnormal cell proliferation, apoptosis, and extracellular matrix deposition. Key findings suggest that abnormalities in arachidonic acid (AA) synthesis and non-essential fatty acid synthesis are integral to keloid formation. Further, a complex interplay exists between lipid derivatives, notably butyric acid (BA), prostaglandin E2 (PGE2), prostaglandin D2 (PGD2), and the regulation of hyperfibrosis. Additionally, combinations of docosahexaenoic acid (DHA) with BA and 15-deoxy-Δ12,14-Prostaglandin J2 have exhibited pronounced cytotoxic effects. Among sphingolipids, ceramide (Cer) displayed limited pro-apoptotic effects in keloid fibroblasts (KFBs), whereas sphingosine 1-phosphate (S1P) was found to promote keloid hyperfibrosis, with its analogue, FTY720, demonstrating contrasting benefits. Both Vitamin D and hexadecylphosphorylcholine (HePC) showed potential antifibrotic and antiproliferative properties, suggesting their utility in keloid management. While keloids remain a prevalent concern in clinical practice, this study underscores the promising potential of targeting specific lipid molecules for the advancement of keloid therapeutic strategies.

RIPK3 Expression in Fibroblasts in an in vivo and in vitro Skin Wound Model: A Controversial Result.

One of the major problems of regenerative medicine is the development of hypertrophic scars and keloids. The protein kinase RIPK3 is involved in necroptosis; however, recent evidence indicates that it also has non-canonical functions, including its involvement in the development of renal fibrosis. The aim of our work was to study the expression of RIPK3 in mouse and human skin models of fibrotic processes. A subpopulation of RIPK3+Vim+ cells was found in both human keloid and a mouse wound, with the cell number being significantly greater in the mouse wound bed compared to healthy skin. Real-time polymerase chain reaction (RT-PCR) detected expression of the Ripk3 and fibroblast biomarkers Acta2, Fap, Col1a1, and Fn1 in the cells isolated from the wound bed, indicating that RIPK3 can be expressed by wound bed fibroblasts. An analysis of the human fibroblasts stained with anti-RIPK3 antibodies demonstrated an increase in the fluorescence intensity in the presence of lipopolysaccharide (LPS) at concentrations of 5, 10, 25, 50, and 100 ng/ml and TGF-β at concentrations of 0.1, 1, 2, and 5 ng/ml compared to the control. At the same time, the expression levels of RIPK3 and fibroblast activation markers in the presence of TGF-β and LPS did not differ significantly from the control. It is possible that RIPK3 expression in wound fibroblasts is not directly associated with fibrotic processes, and that kinase plays a different, yet unknown role in wound healing. KEYWORDS scarring, keloid, skin, fibroblasts, cell culture, RIPK3.

Hypoxia macrophage-derived exosomal miR-26b-5p targeting PTEN promotes the development of keloids.

Hypoxia is the typical characteristic of keloids. The development of keloids is closely related to the abnormal phenotypic transition of macrophages. However, the role of exosomal microRNAs (miRNAs) derived from hypoxic macrophages in keloids remains unclear. This study aimed to explore the role of hypoxic macrophage-derived exosomes (HMDE) in the occurrence and development of keloids and identify the critical miRNA. The expression of CD206+ M2 macrophage in keloids and normal skin tissues was examined through immunofluorescence. The polarization of macrophages under a hypoxia environment was detected through flow cytometry. The internalization of macrophage-derived exosomes in human keloid fibroblasts (HKFs) was detected using a confocal microscope. miRNA sequencing was used to explore the differentially expressed miRNAs in exosomes derived from the normoxic and hypoxic macrophage. Subsequently, the dual-luciferase reporter assay verified that phosphatase and tension homolog (PTEN) was miR-26b-5p's target. The biological function of macrophage-derived exosomes, miR-26b-5p and PTEN were detected using the CCK-8, wound-healing and Transwell assays. Western blot assay was used to confirm the miR-26b-5p's underlying mechanisms and PTEN-PI3K/AKT pathway. We demonstrated that M2-type macrophages were enriched in keloids and that hypoxia treatment could polarize macrophages toward M2-type. Compared with normoxic macrophages-derived exosomes (NMDE), HMDE promote the proliferation, migration and invasion of HKFs. A total of 38 differential miRNAs (18 upregulated and 20 downregulated) were found between the NMDE and HMDE. miR-26b-5p was enriched in HMDE, which could be transmitted to HKFs. According to the results of the functional assay, exosomal miR-26b-5p produced by macrophages facilitated HKFs' migration, invasion and proliferation via the PTEN-PI3K/AKT pathway. The highly expressed miR-26b-5p in HMDE promotes the development of keloids via the PTEN-PI3K/AKT pathway.

Transcriptome network analysis of inflammation and fibrosis in keloids

BackgroundKeloid (KL) is a common benign skin tumor. KL is typically characterized by significant fibrosis and an intensive inflammatory response. Therefore, a comprehensive understanding of the interactions between cellular inflammation and fibrotic cells is essential to elucidate the mechanisms driving the progression of KL and to develop therapeutics. ObjectiveInvestigate the transcriptome landscape of inflammation and fibrosis in keloid scars. MethodsIn this paper, we performed transcriptome sequencing and microRNA (miRNA) sequencing on unselected live cells from six human keloid tissues and normal skin tissues to elucidate a comprehensive transcriptome landscape. In addition, we used single-cell RNA sequencing (scRNA-seq) analysis to analyze intercellular communication networks and enrich fibroblast populations in two additional keloid and normal skin samples to study fibroblast diversity. ResultsBy RNA sequencing and a miRNA-mRNA-PPI network analysis, we identified miR-615–5p and miR-122b-3p as possible miRNAs associated with keloids, as they differed most significantly in keloids. Similarly, COL3A1, COL1A2, THBS2, TNC, IGTA, THBS4, TGFB3 as genes with significant differences in keloid may be associated with keloid development. Using single-cell RNA sequencing data from 24,086 cells collected from normal or keloid, we report reconstructed intercellular signaling network analysis and aggregation to modules associated with specific cell subpopulations at the cellular level for keloid alterations. ConclusionsOur multitranscriptomic dataset delineates inflammatory and fibro heterogeneity of human keloids, underlining the importance of intercellular crosstalk between inflammatory cells and fibro cells and revealing potential therapeutic targets.

Re-recognition of the role of roughness in keloid assessment

BackgroundUnder visual observation, keloids are more rough than normal skin. This roughness may be used to assess the activity and severity of keloids but lacks the support of objective and accurate evidence. The purpose of this study was to verify the role of roughness in the development of keloids and to clarify the advantage of roughness in the comprehensive assessment of keloids. MethodsPatients with keloids who attended Peking Union Medical College Hospital were recruited. Keloids were classified into progressive, stable, and atrophic stages based on the change in size over the past year and blood perfusion. The keloids were evaluated using the Vancouver Scar Scale (VSS) and the Patient and Observer Scar Assessment Scale (POSAS). The roughnesses of the keloid and normal skin were measured using the Phaseshift Rapid In vivo Measurement Of the Skin (PRIMOS), and blood perfusion was measured using laser speckle contrast imaging (LSCI). ResultsThirty-three patients with a total of 81 keloids were included. The surface roughness values Sa, Sq, and Sz of the keloid region were 243.70 (143.85–328.05), 316.20 (179.85–475.20), and 1708.20 (1098.30–4087.20), respectively, which were 4.87, 4.80, and 3.08 times higher than those of normal skin. There were significant differences in roughness among the different keloid stages. A significantly strong correlation between roughness and other assessed indices was found. ConclusionsRoughness as a morphological characteristic is of great value in the evaluation of keloids. It is recommended as an important examination for keloids.